The present invention relates to an automatic electronic sewing machine and, more particularly, to a digital control system of an electronic sewing machine which can automatically form various stitch patterns.
A typical control system of an electronic sewing machine is disclosed in John W. Wurst, U.S. Pat. No. 3,855,956 "SEWING MACHINE STITCH PATTERN GENERATION FROM STITCH DATA STORED IN STATIC MEMORY", patented on Dec. 24, 1974.
In this prior art system, digital information relates to the positional coordinates for each stitch of a predetermined stitch pattern is stored in a read only memory (ROM). The digital information stored in the ROM is applied directly to a driving means for controlling movement of stitch forming instrumentality of the sewing machine. Since the ROM output is applied directly to the driving means, the packaging of the ROM-IC should be the socket type to allow the exchange of the ROM when various stitch patterns are desired to be formed. However, this is not favorable in the sewing machine, because oscillation caused by the stitch forming instrumentality will produce ill connection between the ROM and the control circuit assembly.